Ch 24 Objectives Flashcards
(151 cards)
1
Q
What are previous difficult airway indicators?
A
Chipped or broken teeth, bruised lips, sore throat post-anesthesia, unexpected ICU admission, esophageal or tracheal perforation, memory of a difficult intubation.
2
Q
What changes in airway anatomy should be considered?
A
Weight gain or loss, previous airway tumor or hematoma, post-surgical anatomical changes.
3
Q
Why is a history of difficult airway important?
A
Past records provide critical insight into anticipated difficulties and effective management techniques.
4
Q
What is the significance of current airway assessment?
A
Conditions present in prior surgeries may have resolved or worsened, necessitating a re-evaluation.
5
Q
What is the effectiveness of predictive tests and scores for airway difficulty?
A
No single test is 100% predictive; a combination of assessments is more effective.
6
Q
What are signs of inadequate ventilation?
A
Minimal or no chest movement, absence of exhaled carbon dioxide, reduced or absent breath sounds, decreasing oxygen saturation (< 92%).
7
Q
What are predictors of difficult bag-mask ventilation (BMV)?
A
Mask seal impediments, upper airway obstruction, lower airway obstruction, obesity, and pregnant patients.
8
Q
What are some mask seal impediments?
A
Beard, altered facial anatomy, edentulous patients, nasogastric tube.
Solutions include shaving beard, maintaining dentures, and removing NG tube as needed.
9
Q
What signs indicate upper airway obstruction?
A
Muffled voice, stridor, dyspnea, hoarse voice.
Stridor and dyspnea are ominous signs of severe respiratory obstruction.
10
Q
What are signs of lower airway obstruction?
A
High peak airway pressures, low tidal volumes, impaired ventilation.
11
Q
What challenges do obesity and pregnancy pose for airway management?
A
Obesity decreases functional residual capacity and increases airway resistance. Pregnancy compresses lungs, increasing airway resistance.
12
Q
What management steps should be taken if BMV remains inadequate?
A
Consider inserting a supraglottic airway device, proceed with direct or video laryngoscopy for tracheal intubation, perform a cricothyrotomy if all measures fail.
13
Q
What factors contribute to difficult ventilation?
A
Excessive chest and abdominal tissue, decreased functional residual capacity, redundant soft tissue in the oropharynx and pharynx.
14
Q
What are airway management strategies for obese patients?
A
Optimal positioning, preoxygenation, secondary airway plan, team approach.
15
Q
What is the Modified Mallampati Classification (MMT)?
A
Assesses mouth opening, tongue size, and oropharyngeal space.
16
Q
What are the classes of the Modified Mallampati Classification?
A
Class I: Entire oropharynx, uvula, and tonsillar pillars visible.
Class II: Soft palate, fauces, and uvula visible.
Class III: Only soft palate and base of uvula visible.
Class IV: Only hard palate visible.
17
Q
Which classes of the Modified Mallampati Classification are associated with increased intubation difficulty?
A
Class III and IV.
18
Q
What does the Thyromental Distance (TMD) measure?
A
Measures the distance from the thyroid notch to the chin.
19
Q
What TMD value predicts difficulty in aligning airway structures?
A
Short TMD (< 6 cm).
20
Q
What does the Interincisor Gap Distance measure?
A
Measures mouth opening.
21
Q
What Interincisor Gap Distance value is associated with difficulty in DL and VL?
A
< 4 cm.
22
Q
What does limited Atlantooccipital Joint Mobility indicate?
A
Limited neck extension (< 30°) can impair visualization during DL.
23
Q
What does the Mandibular Protrusion Test assess?
A
Assesses the ability to protrude the mandible forward.
24
Q
What does an inability to advance the lower teeth beyond the upper incisors predict?
A
Predicts difficulty.
25
What neck circumference is a significant predictor of intubation difficulty?
> 43 cm, particularly in obese patients.
26
What factors influence DL, VL, and TI?
Obesity, OSA and Snoring, Advanced Age.
27
What is the significance of obesity in airway assessments?
Excessive soft tissue can obstruct the glottic view.
28
What is the proposed Class 0 in the Mallampati Classification?
Indicates visualization of the epiglottis upon mouth opening without phonation.
29
What is the Cormack and Lehane Grading System?
A standardized grading system used to assess the view of the laryngeal structures during laryngoscopy.
30
What does Grade I of the Cormack and Lehane Grading System indicate?
Full view of the entire glottic opening, including the anterior commissure and posterior laryngeal cartilages.
31
What does Grade IIa of the Cormack and Lehane Grading System indicate?
Partial view of the vocal cords; anterior commissure not seen but the posterior cartilages are fully visible.
32
What does Grade IIb of the Cormack and Lehane Grading System indicate?
Only the posterior portion of the glottic opening is visualized.
33
What does Grade III of the Cormack and Lehane Grading System indicate?
Only the epiglottis is visible; no portion of the glottic opening is seen.
34
What does Grade IV of the Cormack and Lehane Grading System indicate?
The epiglottis is not visible; only the soft palate is seen.
35
What is the clinical significance of Grades I and IIa/b?
Generally associated with easier intubations.
36
What do Grades III and IV indicate in the Cormack and Lehane Grading System?
Indicative of difficult intubation and higher risk of airway obstruction.
37
What is the Percentage of Glottic Opening (POGO) Score?
Quantifies the percentage of the vocal cords visible, ranging from 0% to 100%.
38
What does a 100% POGO indicate?
Full view from the anterior commissure to the interarytenoid notch.
39
What does a 0% POGO indicate?
No part of the glottic opening is visible.
40
How does the POGO Score compare to the Cormack and Lehane scale?
Provides a more quantifiable measure of airway visualization.
41
What does Thyromental Distance (TMD) measure?
The TMD measures the distance from the thyroid notch to the mentum (chin) with the mouth closed and the head extended.
42
What is the normal range for Thyromental Distance (TMD)?
Normal TMD is 6 to 9 cm (approximately three fingerbreadths).
43
What does a short Thyromental Distance (TMD) indicate?
A short TMD (< 6 cm) indicates a small thyromental space, potentially obstructing the line of sight to the glottic opening and is associated with difficult laryngoscopy and intubation.
44
What conditions are commonly associated with a short TMD?
Conditions like tumors, radiation, and mandibular hypoplasia.
45
What does a long Thyromental Distance (TMD) indicate?
A long TMD (> 9 cm) indicates a large hypopharyngeal tongue, caudal larynx, and longer mandibulohyoid distance (MHD), which may result in difficulty aligning the glottic opening with the visual axis.
46
What is the 3-3-2 Rule?
A simple assessment tool to evaluate upper airway geometry using fingerbreadths as a measurement unit.
47
What does the first '3' in the 3-3-2 Rule represent?
The first '3' represents the mouth opening (interincisor gap) which should be three fingerbreadths.
48
What does the second '3' in the 3-3-2 Rule represent?
The second '3' represents the Thyromental distance (TMD) from mentum to thyroid notch which should be three fingerbreadths.
49
What does the '2' measurement in the 3-3-2 Rule represent?
The distance from the thyroid notch to the hyoid bone should be two fingerbreadths.
50
What does a Sternomental Distance (SMD) measure?
SMD measures the distance from the sternal notch to the mentum (chin) with the mouth closed.
51
What is the normal range for Sternomental Distance (SMD)?
Normal SMD is > 12.5 cm to 15 cm.
52
What does a short Sternomental Distance (SMD) indicate?
A short SMD (< 12.5 cm) is associated with difficult laryngoscopy and intubation, indicating limited neck extension.
53
What does a long Sternomental Distance (SMD) suggest?
A long SMD (> 15 cm) suggests a longer hypopharyngeal space, possibly hindering visualization.
54
What is the Interincisor Gap?
The interincisor gap is the measurement of the distance between the upper and lower incisors when the mouth is fully opened.
55
What is the normal range for Interincisor Gap?
Normal range is at least 3 cm (approximately 2-3 fingerbreadths).
56
What does a narrow Interincisor Gap (< 3 cm) indicate?
A narrow Interincisor Gap is associated with difficult laryngoscopy and intubation, limiting visualization.
57
What factors affect the Interincisor Gap?
Factors include maxillary incisor length, loose or malpositioned teeth, and edentulous patients.
58
What does Atlantooccipital Joint Mobility refer to?
It refers to the degree of neck flexion and extension, essential for achieving the sniffing position.
59
What is the normal range for Atlantooccipital Joint Mobility?
Full neck extension varies from 90 to 165 degrees, with an average head extension of up to 35 degrees.
60
What is the clinical implication of reduced Atlantooccipital Joint Mobility?
Extension < 23 degrees is associated with difficult laryngoscopy and intubation.
61
What are management options for limited Atlantooccipital Joint Mobility?
Videolaryngoscopy (VL) and fiberoptic scope are effective for improved visualization.
62
What does the Mandibular Protrusion Test assess?
It assesses the ability to move the lower incisors anteriorly past the upper incisors.
63
What does the Mandibular Protrusion Test indicate?
It indicates the degree of temporomandibular joint mobility and mandibular function, critical for positioning for DL.
64
What is Class A in the Mandibular Protrusion Test classification?
Lower incisors protrude anteriorly past the upper incisors, and the patient can bite the upper lip above the vermilion border.
## Footnote
Indicates favorable intubation view.
65
What is Class B in the Mandibular Protrusion Test classification?
Lower incisors can be aligned with the upper incisors but cannot pass beyond them, and the patient can bite the upper lip below the vermilion border.
66
What is Class C in the Mandibular Protrusion Test classification?
Lower incisors cannot be aligned with the upper incisors and cannot bite the upper lip.
## Footnote
Indicates difficult laryngoscopy and intubation.
67
What does Class C suggest about mandibular mobility?
It suggests reduced mandibular mobility, limiting the ability to displace the tongue and visualize the glottis during DL.
68
How reliable is the ULBT in edentulous patients?
The ULBT is considered less reliable due to altered mandibular anatomy.
69
What is the application of the Mandibular Protrusion Test?
It is useful in combination with other assessments, such as Mallampati classification and neck circumference.
70
What are the limitations of the Mandibular Protrusion Test?
It has limited predictive value when used in isolation, especially in patients with dental prosthetics or edentulous anatomy.
71
What are some factors that contribute to difficult mask ventilation?
Beard, Obese, No teeth, Elderly, Sleep apnea (snoring)
72
What should be evaluated for difficult laryngoscopy and intubation?
Look externally (shape of face, morbid obesity, pathology of the head and neck), Evaluate 3-3-2 rule, Mallampati score, Obstruction, Neck mobility
73
What factors indicate difficult supraglottic airway placement?
Restricted mouth opening, Obstruction, Distorted airway, Stiff lungs or C-spine
74
What factors indicate difficult surgical airway placement?
Surgery (neck surgery or previous scar), Hematoma, Obesity, Radiation (or other deformities), Tumor
75
What are the types of difficult airway management?
Difficult intubation, Difficult supraglottic airway, Difficult invasive airway
76
What separates the upper airway from the lower airway?
The cricoid cartilage separates the upper airway from the lower airway.
77
What are the components of the upper airway?
Nose, Mouth, Pharynx, Hypopharynx, Larynx, Cricoid Cartilage.
78
What are the components of the lower airway?
Trachea, Bronchi, Bronchioles, Terminal Bronchioles, Respiratory Bronchioles, Alveoli.
79
What are the functional roles of the upper airway?
Filters, warms, and humidifies inspired air. Acts as the first line of defense against pathogens.
80
What is the functional role of the lower airway?
Facilitates gas exchange through alveolar structures.
81
What embryologic structures contribute to the formation of the upper airway?
Arises from optic, olfactory, and otic capsules. Mesodermal ossification forms structures like the ethmoid, sphenoid, and occipital bones.
82
How many pharyngeal arches are there?
Six arches (first to fourth, sixth arch, fifth disappears).
83
What does the 1st pharyngeal arch develop into?
Jaws, anterior two-thirds of the tongue.
84
What does the 2nd pharyngeal arch develop into?
Facial structures and ears.
85
What does the 3rd pharyngeal arch develop into?
Hyoid bone and upper pharynx.
86
What do the 4th and 6th pharyngeal arches develop into?
Larynx and lower pharynx.
87
What happens to the 5th pharyngeal arch during development?
It disappears.
88
What forms during embryogenesis related to clefts and pouches?
External clefts and internal pouches form during embryogenesis.
89
What is an example of a cleft formed during embryogenesis?
The cleft between the first two arches becomes the external auditory meatus.
90
What are the primary functions of the nose?
Primary entry point for air. Warms, humidifies, and filters inspired air through its large surface area.
91
What role do turbinates play in the nose?
Turbinates cause directional airflow changes, aiding in humidification.
92
What are the three main arteries supplying blood to the nose?
Maxillary (Sphenopalatine) Artery, Ophthalmic Artery, Facial (Septal) Artery.
93
What nerve provides sensory innervation to the nose?
Trigeminal nerve (V1- ophthalmic, V2 - maxillary).
94
What is the sympathetic innervation of the nose?
Superior cervical ganglion (causes vasoconstriction = shrinks nasal tissue).
95
What is the parasympathetic innervation of the nose?
CN VII: Facial nerve & pterygopalatine ganglion (causes vasodilation = e.g., risk of increased bleeding with general anesthesia).
96
What are the effects of general anesthesia on the nasal mucosa?
Sympathetic depression can cause nasal mucosa engorgement, increasing bleeding risk during nasal intubation.
97
What separates the oral cavity from the nasal passages?
The hard and soft palates.
98
What is the function of the hard palate?
Bony and stationary.
99
What is the function of the soft palate?
Flexible, rises during swallowing to prevent nasal regurgitation/aspiration.
100
What role does the tongue play in the oral cavity?
Fills most of the oral cavity, involved in taste and ingestion.
101
What factors can increase the risk of airway obstruction?
Age, obesity, or other conditions can stretch airway structures, increasing the risk of obstruction during sleep or under general anesthesia.
102
How can the tongue contribute to airway obstruction?
Relaxes during sleep or paralysis, potentially obstructing the airway.
103
What is the function of the uvula?
Protects the passageway from the oral cavity to the oropharynx.
104
What can happen if the uvula is swollen or injured?
It can obstruct the airway.
105
Where are the palatine tonsils located?
At the posterior opening of the oral cavity.
106
What can contribute to airway obstruction if enlarged?
Palatine tonsils.
107
What can lead to airway obstructive disorders?
Underdevelopment of the tongue, maxilla, or mandible.
108
What are some syndromes associated with airway obstruction?
Beckwith-Wiedemann and Down syndrome can cause macroglossia, increasing the risk of airway obstruction.
109
What is the anatomical location of the pharynx?
The pharynx extends from the base of the skull to the level of the cricoid cartilage.
110
What are the boundaries of the nasopharynx?
The nasopharynx is located between the skull base and soft palate and contains adenoids and Eustachian tube openings.
111
What is the oropharynx and its boundaries?
The oropharynx is located between the soft palate and epiglottis, including tonsillar pillars.
## Footnote
Opening into oropharynx = fauces (used in Mallampati classification)
112
What is the hypopharynx and its boundaries?
The hypopharynx (laryngopharynx) is posterior to the larynx, extending from the epiglottis to the cricoid cartilage, including the upper esophageal sphincter.
## Footnote
This muscle acts as a barrier (within the upper esophagus) to prevent regurgitation in a conscious patient.
113
Which nerves supply motor and sensory fibers to the airway?
The glossopharyngeal, vagus, and spinal accessory nerves supply motor and sensory fibers to the airway, sharing nuclei in the medulla.
114
Which nerve provides sensory innervation to the nasal cavity?
The trigeminal nerve provides sensory innervation to the nasal cavity.
115
What is the afferent pathway of the gag reflex?
Afferent stimuli from the pharynx are carried by the glossopharyngeal nerve to the medulla.
116
What mediates the efferent response in the gag reflex?
The efferent response is mediated through the vagus nerve, causing pharyngeal muscle contraction and elevation.
117
What are the branches of the vagus nerve?
The vagus nerve branches into the Superior Laryngeal Nerve (SLN) and the Recurrent Laryngeal Nerve (RLN).
118
What does the internal branch of the SLN provide?
The internal branch of the SLN provides sensory input to the hypopharynx above the vocal cords, including the posterior tongue, epiglottis, aryepiglottic folds, and arytenoids.
119
What is the function of the external branch of the SLN?
The external branch of the SLN provides motor function to the cricothyroid muscle.
120
What does the RLN provide sensory input to?
The RLN provides sensory input to the subglottic area and trachea.
121
How does the right RLN differ from the left RLN?
The right RLN loops around the right subclavian artery; the left RLN loops around the aortic arch.
122
What is the motor function of the RLN?
The motor component of the RLN provides motor function to all the muscles of the larynx except the cricothyroid muscle.
123
What are the implications of unilateral RLN injury?
Unilateral RLN injury results in hoarseness without respiratory distress; vocal cords shift midline toward the uninjured side.
124
What occurs during bilateral RLN injury in the acute phase?
Bilateral RLN injury in the acute phase causes vocal cord adduction and unopposed tension, leading to stridor and potential respiratory distress.
125
What are the effects of chronic bilateral RLN injury?
Chronic bilateral RLN injury allows compensatory mechanisms for normal respiration but results in a husky or gruff voice.
126
What is the implication of SLN injury?
SLN injury is not typically associated with respiratory distress.
127
What can compress or injure the RLN?
Surgical traction, neck trauma, neoplasms, and aortic arch aneurysms can compress or injure the RLN, leading to hoarseness or airway obstruction.
128
What conditions can cause left RLN compression?
Mitral stenosis and aortic arch aneurysms can cause left RLN compression.
129
What triggers the gag reflex?
Stimulation of the posterior pharynx via the glossopharyngeal nerve triggers a response via the vagus nerve.
130
What are the three main structures of the larynx?
The larynx is composed of cartilages, paired cartilages, and intrinsic and extrinsic muscles.
131
What are the single cartilages of the larynx?
The single cartilages are the thyroid, cricoid, and epiglottis.
132
What are the paired cartilages of the larynx?
The paired cartilages are the arytenoid, corniculate, and cuneiform.
133
What is the function of intrinsic muscles of the larynx?
Intrinsic muscles control the tension of the vocal cords and the opening/closing of the glottis.
134
What is the function of extrinsic muscles of the larynx?
Extrinsic muscles connect the larynx, hyoid bone, and adjacent structures, adjusting the position of the larynx during phonation, breathing, and swallowing.
135
What are the functions of the larynx?
The functions include protection of the lower airway, maintaining patency, activating reflexes, and phonation.
136
What is the anatomical location of the larynx?
The larynx extends from the 3rd to the 6th cervical vertebra (C3-C6).
137
What forms the anterior structures of the larynx?
The thyroid cartilage forms the anterior and lateral aspects, connecting to the hyoid bone via the thyrohyoid membrane.
138
What is the role of the epiglottis?
The epiglottis closes during swallowing to prevent aspiration.
139
What is the blood supply to the larynx?
The arterial supply is derived from the external carotid artery and the inferior thyroid artery.
140
What is the origin and length of the trachea?
The trachea begins at the inferior border of the cricoid cartilage and extends to the carina, approximately 10 to 20 cm in adults.
141
What is the structure of the trachea?
The trachea is composed of 16 to 20 C-shaped cartilaginous rings, with the cricoid cartilage being the only complete ring.
142
What is the function of the trachealis muscle?
The trachealis muscle allows the esophagus to expand during swallowing and constricts the trachea during coughing.
143
What is the angle of bifurcation for the right mainstem bronchus?
The angle of bifurcation for the right mainstem bronchus is 25 to 30 degrees.
144
What is the angle of bifurcation for the left mainstem bronchus?
The angle of bifurcation for the left mainstem bronchus is 45 degrees.
145
What is the function of the bronchi?
The bronchi humidify and warm inspired air as it passes towards the alveoli.
146
What is the clinical significance of the carina?
The carina is highly sensitive to sensory stimulation, making it a common site for triggering coughing during tracheal manipulation.
147
What is the origin of sympathetic innervation to the bronchi?
Sympathetic innervation originates from the first through fifth thoracic ganglia.
148
What is the origin of the phrenic nerve?
The phrenic nerve originates from C3, C4, and C5 spinal nerves.
149
What are the four embryonic structures that give rise to the diaphragm?
The four embryonic structures are the septum transversum, dorsal esophageal mesentery, pleuroperitoneal folds, and body wall mesoderm.
150
What can result from a diaphragmatic hernia?
A diaphragmatic hernia allows abdominal contents to herniate into the thoracic cavity.
151
What can happen due to phrenic nerve injury?
Phrenic nerve injury can result in diaphragmatic paralysis, causing paradoxical movement or respiratory distress.
